Handheld vacuum cleaners are well known and have been manufactured and sold for several years. Typically, a handheld vacuum cleaner comprises a body which houses a motor and a fan unit for generating an airflow. The airflow enters the vacuum cleaner via an inlet. A separator such as a filter, bag or cyclonic separator is located downstream of the inlet to separate dirt and dust from the airflow. An example of this type of vacuum cleaner is shown in GB 1 207 278.
Handheld vacuum cleaners are generally powered by brushed carbon motors, and therefore it is common to have a post motor filter in order to catch carbon released from the brushes of the motor. Such a filter also advantageously reduces the noise of the vacuum cleaner during use.
Although brushed carbon motors are adequate, there has been a desire to increase the power of the motor to improve the performance of vacuum cleaners. In order to achieve this brushless DC motors are now being used. Brushless DC motors are more powerful and smaller than conventional motors and no longer require the use of post motor filters because no carbon is produced. As stated above a post motor filter reduces noise and therefore if it is not present, another noise reducing device would be desirable.
In addition, it is generally desirable for cleaning appliances to be as quite as possible during use. Therefore any new sound reducing mechanism in a cleaning appliance would be desirable.